WASHINGTON -- A second woman who worked for Supreme Court nominee Clarence Thomas will be called to testify against him today, complaining of his "unwelcome and inappropriate" advances toward her, sources in the administration and in Congress said last night.

The woman, identified by those sources as Angela D. Wright, 37, had declined to appear before the Senate Judiciary Committee unless ordered to do so and now has apparently been subpoenaed to testify, the sources said.

The first woman to complain about sexual misconduct by Judge Thomas as a supervisor was Anita Faye Hill, a legal aide to him when they both were in the government. He denies her accusations of sexual harassment.

Ms. Hill, now a law professor at the University of Oklahoma, had already been scheduled to testify today -- probably after Judge Thomas testifies. He will have a chance to come back later to answer her.

It was unclear last night whether an appearance by Ms. Wright, now an editor at the Charlotte (N.C.) Observer, was definite. She was interviewed by committee staff members by telephone yesterday.

The specific nature of the testimony she would give was unclear, but Ms. Wright told the Knight-Ridder news service that she had informed Senate investigators that, when she was a press aide at the Equal Employment Opportunity Commission, Judge Thomas repeatedly pressured her for dates.

She also said that, on one occasion, he "asked me what size my breasts were." At a banquet, she related, he said she looked nice and then said, "What size are your breasts?"

"I just said something like, 'Don't you think you ought to be familiarizing yourself with the speakers?' " she said. "I would usually ignore it and move on to the next level."

In addition, she related that Mr. Thomas had appeared uninvited at her apartment in Washington. It was unclear whether the incidents she related to Senate investigators had all occurred while she was on the EEOC staff and he was the chairman.

She told an interviewer last night that she was "not stating a claim of sexual harassment against Clarence Thomas. It's not something that intimidated or frightened me. At the most, it was annoying and obnoxious."

Although EEOC officials said she was fired from her post by Mr. Thomas, one of her editors at the Charlotte newspaper said that Mr. Thomas had said specifically last January that she had resigned and was an "excellent employee," and that he gave her a positive recommendation for a job.

The revelation of the new witness added to the impression that Judge Thomas' difficulty could be deepening, perhaps frustrating his goal of testifying to save his reputation and -- maybe -- to save his chances of becoming a Supreme Court justice.

Throughout the day yesterday, rumors had circulated here that at least one more woman would be summoned as an anti-Thomas witness for the reopened hearings on his nomination -- hearings that are to be confined solely to claims of personal misconduct by the nominee.

In early evening, the White House issued a brief statement saying that it had been told by the Judiciary Committee staff that "another witness" would be called "to testify against Judge Thomas. . . . We cannot discuss the details of this matter, but Judge Thomas will deal with this in the course of the hearings."

The White House refused to confirm the identity of that witness, but other sources identified her as Ms. Wright.

In its statement, the White House said that the committee staff had not followed "the normal practice" of asking the FBI to HTC investigate a new complaint before deciding to summon the witness.

In what senators have warned repeatedly would be a painful and even wrenching conflict, the 43-year-old judge and Ms. Hill, and possibly Ms. Wright, were expected to tell the Senate Judiciary Committee their competing versions of their dealings with each other some years ago, and since.

The three -- a candidate for the nation's highest court accused of sexual misconduct, and two female accusers -- are not likely to confront each other face to face. Their testimony would be separated; the committee also planned to question perhaps a half-dozen other witnesses.

Among the witnesses expected to support Ms. Hill's version of her experiences are a former Yale Law School classmate and now California state official, Susan J. Hoerchner; an American University law professor, Joel Paul; and Ellen Wells, who knew Ms. Hill at the time of the alleged misconduct.

She also will get the support of character witnesses, including David Swank, the dean of the University of Oklahoma Law School where she teaches, and Stanford law professor Kim Taylor.

It was unclear last night whether any additional witnesses would appear to support Ms. Wright.